TheSamba.com :: View topic - Which heads, manifold, carburetor combination should I run?

Sun May 19, 2019 6:47 pm

Back in September (Build Thread) my son and I found a sweet deal on a VW Baja Money pit :D We've put a bunch of work into it and had a blast. All of that made possible by help from Samba members! I need your help again.

A couple of weeks ago, my son blew up the engine (two rods through the case). It could have just been that the motor was done, but I suspect it has to do with teenage inexperience, low oil, and RPM.

The old motor was a 1600 dual port with and 009 dist, dual port intakes and a double barrel weber IDF 40 carb.

I have another donor motor we are going to stick on the bug. I'm told it was a running motor - we'll see how it looks after tearing it down. It came with some extra parts and I need some help deciding what to run.

The new motor (I'm told - no stamp on the case) is a 1600 single port, 009 dist, and was running a single barrel Solex H30/31PICT carb. But, the owner also gave me a double barrel weber 44 IDF carb with a double barrel intake.

When the engine blew up, it ruined just about everything, but the dual port heads seem to be ok. So, do we:

A: run the new single port motor with the Solex Carb
B: swap the heads onto the new motor and run the IDF 40
C: swap the heads onto the new mortor and run the IDF 44
D: Do something else that I don't know about because I'm still pretty new to all of this.

Side note: it will see about half an half on road and off road driving. We're more concerned with the off road performance. Gas Mileage and top speed are secondary. The car is running an 091 bus trans.

I won't go into the reasons why, but whatever we do right now just needs to get the bug running through July. At that point, the car will probably sit for two years while my son is off in Peru for a while. when he gets back, it will probably get a bigger engine, a paint job, and some other goodies. So, he really needs to invest the minimum viable amount of money into it right now.

Here are some images of what we have:

original Dual port heads:

Original Double Barrel Weber 40 IDF carb:

Sigle port head on new motor:

Weber Double Barrel 44 IDF carb that came with motor purchase:

Original Single Barrel Pict Carb and Intake:

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Sun May 19, 2019 7:50 pm

I was going to run dual 34 ict carbs from cbp on my single port. But I believe most suggest a single carb on off-road stuff for simplicity

Sun May 19, 2019 8:42 pm

Single carbs are the plan. I just need to know if I should use my single port heads and the Pict carb or my double port heads and my weber 40IDF or 44IDF double barrel carb.

And, if I go with the dual port heads, are there any 'gotchas' I need to know about on the swap. What I've read says that I have to change some studs (which I have available) and some of the tin (which I also have). Is there anything else?

Sun May 19, 2019 9:46 pm

Well the heads need to be in good order. Which are the best? Are you rebuilding the dual port heads? If so They are always going to give the best performance. A 1600 can't really handle a 40 IDF let alone a 44 however the 40 IDF as a single on dual port heads will on outperform the single port heads not that they would be bad or anything. The 40 will need properly jetting to run as a single and it will work best with a smaller venturi as it's a 1600. I would try the 28mm venturis. This rig is going to need heat risers. Is it a dogHouse?

Mon May 20, 2019 6:59 am

@danwvw - I have both styles of fan shroud (dog house and non) - we will be running the dog house style.

The motor my son blew up was a 1600 (dual port) running the single weber 40 IDF, but we never had gotten the jetting exactly right. I think that is the configuration we want to go back to.

We weren't going to rebuild the heads, but we can. What should I be looking at to make sure the heads are in good order?

Mon May 20, 2019 8:53 am

I have always gone for the dual carbs, 009, big exhaust thing & it was fun but I took my Ghia back to a bone stock, 1600 single port with a doghouse shroud with all of the correct linkages, thermostat, tins, carb, & SVDA distributor & have put 19,000 (mostly (crappy condenser & distributor cap.)) trouble free miles without having to screw with carb adjustment, blipping the throttle to get past the dead spot, or hard start issues in all temperatures, elevations, & weather conditions. And it was cheaper too. While "under powered", it's still WAAYY too easy to exceed the limits of traction & braking.

Wed May 22, 2019 5:13 am

44 will be to big for either combo. If you were doing the dual port 1600 with some upgrades, the single 40 would be good. Stock 1600 I'd go with the PICT 34.

Wed May 22, 2019 1:49 pm

For sure the best running engine can be had going with Dual 40 IDF's over a single. But in the dirt a lot of guys prefer the single carburetor as it doesn't get as much dirt in it. The 40 IDF single has been covered many times here on the Samba and usually it gets totally different Jetting than the Dual carbs would. Which Emulsion Tube does it have? Main Jet size? Venturi size, Idle jet size? Accelerator Pump Jet sizes etc...

Heads? Will, if you know they are low mileage, then maybe just clean them up. Inspect for cracks around spark plugs and valves etc...
The big thing needed usually with the heads is to check valve guide wear and valve spring pressure. Depending on the cam they may need upgraded valve springs. On a 1600 cc your better off staying away from larger valve sizes especially off road. If the Valve guides are only a little bit wallowed out they can be knurled by a VW Machine shop which saves changing the guides. Generally though these days people are just buying new inexpensive heads for their rebuilds. Something like the AA Performance Series 500's are nice as they have 3/4" Reach SparkPlug Holes and Single HD Valve Springs and SS valves etc... Mofoco Super Street, AirCooled.Net, and Tims Super Stock all offer improved near stock heads for 1600cc engines too.
Consider Solid Rockers and Scat Ball adjusters too.

Wed May 22, 2019 11:25 pm

2 rods thrown? :shock:

That's more than I've EVER done...

Suggests a serious missed shift. Like downshift from 4th to 1st...

Shortage of oil will tend to seize the main bearings before it throws a rod.

I would personally choose the single IDF on dual port heads. Clean the heads up and inspect.

But if Junior is so over-exuberant, maybe he needs to be calmed down a bit with the single Solex.

Tue Jun 04, 2019 1:23 pm

Thanks for all the help. We went with the dual heads and Weber 40IDF carb. It runs better than the previous motor. It should easily get him by until he leaves in July. When he gets back we'll look at putting something with a little more HP in it.